Hi again. I don't know much about how combustion engines work but I doubt that the Massimo engine is gravity lubed. So, I just finished the oil change and in place of a traditional oil filter there is a "oil strainer" on a spring that connects to the drain plug. There's an oil pump so that doesn't sound like a gravity system to me. This is the advertised description of the engine "NEW 391cc HO [High Output] Four-Stroke, liquid cooled engine actually generates more HP then our legendary MSU 500! The HO single cylinder power plant utilizes “advanced bypass oil filter technology.” With this bypass system owners can prolong oil intervals. " In any event, we have a hobby farm and this machine is perfect for us, especially given the price I paid - $6000 CDN plus tax. That's less than $5000 US. Now, this is a Chinese machine assembled in Texas so I'm keeping my fingers crossed regarding reliability.